1. Field of the Invention
This invention pertains to control circuits for lighting systems and more particularly to control circuits permitting remote take control of dimming operations, rate of dimming and the like in high intensity discharge lamp systems.
2. Description of the Prior Art
It is only a fairly recent development that high intensity lighting systems have been equipped with the capacity to dim. The advent of this development is represented by the dimming circuit shown in U.S. Pat. No. 3,816,794. More recently, a more sophisticated system has been developed, as disclosed in U.S. Pat. No. 3,894,265.
Lighting systems with which such a dimming circuit are employed are often quite large, involving tens and sometimes even hundreds of individual lights deployed over large areas. It is a distinct advantage to be able to control the system from more than one location, such as at two doorway locations at the opposite ends of a large building. In fact, it is very desirable to have the ability to provide full control at numerous locations.
Through experience, it has developed that it is not only desirable to change the amount of light intensity of a lighting system, but also to change the rate of intensity change from bright to dim or from dim to bright.
Therefore, it is a feature of the present invention to provide improved apparatus for permitting the full take over of dimming controls for a high intensity lighting system at a plurality of locations.
It is another feature of the present invention to provide an improved apparatus for permitting full takeover of intensity and rate of dimming for a high intensity discharge system at a plurality of locations.
It is still another feature of the present invention to provide an improved apparatus for permitting full takeover of on/off and of dimming functions for a high intensity discharge system at a plurality of locations, a visual indication also being provided to indicated that a given "take control" station is operating the system.